The following two projects are a part of structural studies of subunit c of E. coli F0F1 ATP synthase in chloroform/methanol/water solvent conducted in our lab. 1. The c subunit in vivo forms a regular complex of 9-12 protein molecules. We plan to try to elicit complex formation in organic solvent by varying its composition. The aggregation state of the protein will be monitored by measuring t1 and t2 in inversion-recovery experiments. 2. Experiments with the native enzyme indicate that one of the c subunit mutants generated in our lab may specifically bind Li+ ions, a most unusual property, since the wild type enzyme displays absolute specificity for H+. We will investigate whether the purified mutant protein binds Li+ in organic solvent. The first step, now underway, is to look at 1D difference spectra collected under various conditions qLi+. Since most of the assignments are already available for wild type protein, residues involved in the interaction with Li+ ions could be identified by DQF-COSY experiments. This program will probably take 3-4 months and requires the use of 5 mm 1H-probe on DMX-600 or DMX-500 spectrometer.